This invention relates to a method and apparatus to allow for the boosting of pipeline pressure for pipelines conveying large particle solids such as coal in a fluid medium.
A known method of boosting pressures in pipelines with a fluid medium consists of a centrifugal pump placed in series with the pipeline. The pump receives the fluid medium from the pipeline and boosts the pressure by centrifugal force of an impeller and discharges the fluid medium at higher pressure into the continuation of the pipeline. Centrifugal pumps are well known for capability of boosting pressure of slurries with solid particles usually less than 1/2 inch, entrained in a liquid. Generally, severe wear is encountered on the pump impeller and housing due to the impact of the solids on the impeller blades and housing. This impact is a result of the high velocity of the impeller needed to accomplish the pressure boosting. As the size of solid particles increases, the wear becomes more series because the larger mass of the particle creates a greater impact force. Centrifugal pumps have been lined with rubber to reduce the imapct abrasion. Although rubber lining has assisted in reducing wear, it has not wholly allowed pumps the capability of effectively pumping large solids. Technical difficulties arise with very large solids in being able to pass them through the impeller without plugging.
Other proposals for boosting pressures in pipelines carrying a fluid transporting coal or the like--such as shown in U.S. Pat. Nos. 2,672,370 and 2,672,371--are able to avoid the problem of running the particles directly through the pump, but they have the problem of requiring a separate source of supply of clear water (thus restricting the localities in which the method may be economically practiced), and require two parallel transfer pipe sections each of which are from 264 to 5280 feet long (resulting in increased expense for materials and the need for more space). The method of the present invention avoids all of these problems, while the basic apparatus for practicing it is known and proven, and the whole method is extremely simple.
According to the method of the present invention, a liquid of a given fluid pressure transporting coal or the like from a first point of low pressure is confined along a continuous flow path to a second point of higher fluid pressure, successive volumes of solids particles larger than a predetermined size are substantially continuously removed at a transfer point from communication with said flow path, the fluid pressure of the liquid flowing in the flow path downstream of the transfer point is boosted at a boosting point, and successive removed volumes of solids particles entrained with liquid are substantially continuously communicated with said liquid of boosted fluid pressure flowing along said flow path downstream of the boosting point. In this way, a continuous flow of fluid is maintained and boosted in pressure by simple means without the necessity of large and complicated structures for facilitating the boosting and without damage to boosting apparatus.
It is a principal object of this invention to provide a method and apparatus of simply removing large solids, usually greater than 1/8 inch, from a continuous liquid flow prior to entry of liquid into a pump, thus allowing only liquid and small particles to be worked upon by the pump. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and the appended claims.